There are many applications in which a centralized supervisory arrangement of amplifiers controls the performance of sensing, measuring, and controlling functions of remote site. Interconnecting leads between the remote site and the supervisory arrangement are necessary, and may be as much as twelve feet long. A very convenient form of interconnection is known as ribbon cable, in which many mutually insulated conductors extend side by side in a tape or ribbon.
It will be appreciated that the rapid rise and fall of current with accompanies relay energization and de-energization unavoidably produces electrical noise in adjacent conductors: this noise may interfere with or even entirely compromise measurement signals in the adjacent conductors, or even in conductors entirely remote from the noise producing conductor.